In addition to its role in promoting heart disease, numerous studies have also linked red meat consumption to cancers of various kinds, and especially colon cancer. All mammals except for humans contain on the surfaces of their cells a sugar, called Neu5Gc. When humans eat the meat of cows and pigs, we are consuming Neu5Gc, causing this sugar to stick to the outsides of our cells. Because it is not a sugar that humans are meant to have stuck on our cells, our bodies mount an immune response against the cells with surface Neu5Gc, making antibodies that attack those cells. Daily consumption of red meat causes an ongoing immune response resulting in a state of chronic inflammation. Chronic inflammation is now understood to be the chief driver of heart disease, diabetes, and cancers, among other chronic diseases. Dr. Ajit Varki, at UCSD, has shown that this chronic inflammatory state results in spontaneous cancer tumors in mice genetically engineered to not produce Neu5Gc (like humans) when they are fed meat.

There are many reasons to cut down or avoid eating meat, including animal cruelty, pollution effects of cattle, and the various hormones, antibiotics, and grain feeds on which commercial cattle are raised. My recommendation for optimal health is this: if you are going to eat red meat, do so no more than one to three times per month, and buy only organic, pasture raised, animal-centered, grass-fed beef. ​